Hot Tub Water Heating Options

[KenZ71]

So, I picked up a used Thermo-Spas it runs well and keeps the water at the temp set when covered. When the cover is off while we are using it the tub loses about 1 degree every 15 minutes. This is with air temps in the 30s.

Tub is heated / powered by a single 20amp/ 120 volt electric heater. From searching other threads I've learned 220 volts will give better/ more consistent heat. But if I change the heater should I go with Natural Gas instead? We already have gas service in the house so it should be easy.

[Dr. Spa™ Ret.]

Probably not as easy as you think, and the cost of the conversion tends to be so high, you'll never recoup it in energy cost savings. Simply converting to 220v (and the heater you already have should be capable of handling this), will give you 4 times the heating rate. The spa you have is almost certainly able to be convered to 220v, with some simple wiring changes.

[KenZ71]

Simple wiring changes as in pull a new cable that can supply 220 volts, upgrade the breaker, and hook up to the heater? That would be too easy!

Many thanks for the insight, much appreciated.

I have an email into the tub manufacturer with the serial number to see if the heater will support 220 volts.

Anyone need a slightly used 20 amp / 110 volt GE gfci breaker? 

[DaveMc]

Outdside the box:---Introduce a heat exchanger---run a loop from the hot water/solar water heater to a heat exchanger---then another loop from the spa to the exchanger and back------run the loop via 2 small 220 circulating pumps---run at set periodic times dependent upon average temps--like midnight and 6 am for 20 minutes to half an hour.  All of this will heat the water without using your heater.

Ready for critic's:

[KenZ71]

That is pretty much what I was thinking. Apex tubing makes stuff like this very easy. The exchanger would be the most difficult, but a water heater tank would work quite well.

As said above "Ready for critics "